Proposal for a PMD for 400GBASE-SR16

Week of May 12, 2014 Norfolk, VA

Nathan Tracy

Supporters

• Ryan Latchman, Macom• Sharon Lutz, USConec• Tom Palkert, Molex• Scott Sommers, Molex• Pravin Patel, IBM• Mike Tryson, TE• Jeffery Maki, Juniper• David Lewis, JDSU• Scott Kipp, Brocade

page 2

Overview

• Baseline proposal for a retimed PMD to address 802.3bs objective to “provide a physical layer specification which supports a link distance of at least 100m over MMF”.– Leverage the 100GBASE-SR4 draft significantly to re-use the 25G lane

definition for a 400G solution– 16 lane parallel, short wavelength based PMD for 400GBASE-SR16– 100m reach is enabled by making use of the physical layer specifications

from 802.3bm including KR4 FEC defined in 802.3bj Clause 91– Use OM4 fiber– Allow either MT ferrules in MPO connectors OR Prism® MT ferrules in

MXC™ connectors

page 3

Rationale

• 25G optical lanes are being defined in 802.3bm Clause 95 operating at 25.78125Gb/s based on:– OM4 Multimode fiber– 850nm VCSEL lasers– 4 parallel bit streams in each direction (100Gbs)

• Can be expanded to 16 lane format for 400Gb/s– Use of the CDFP form factor will result in significant density increase

over 100GBASE-SR4. Other form factors are possible as well.

page 4

16 plus 16 MM fibers

PMA/PMD

MDI

CDAUI-16

16 channel parallel optical RX and retimers

16 channel parallel retimersand optical TX

MACPCSFECPMA

MACPCSFECPMA

400G Proposal

page 5

L14

L15

L14

L15

&

TP1<0:15> TP2<0:15> TP3<0:15> TP4<0:15>

15 15

Block Diagram of 400GBASE-SR16

page 6

• Propose to use same TX values as Table 95-6 once they are finalized– TDP and TxVEC issues

still being discussed

Table X-X – 400GBASE-SR16 transmit characteristics

TX Characteristics

page 7

• Propose to use same RX values as Table 95-7 once they are finalized

Table X-Y – 400GBASE-SR16 receive characteristics

Rx Characteristics

page 8

Fiber Optic Cabling

• OM4 cabling should be used for the 100m reach objective• Interconnects can use two ferrule options:

– The 2x16 fiber Physical Contact MT ferrule that is currently being defined in IEC– The 2x16 fiber Expanded Beam Prism® MT ferrule

• Propose to allow both options as follows:– 2x16 physical contact MT Ferrule will be housed in the standard MPO

connector body• IEC and TIA are in process of documenting this ferrule

– 2x16 Prism ® MT will be housed in the MXC™ connector body• Link to Open Compute MXC™ information:

http://www.opencompute.org/assets/Uploads/Open_Compute_Project_Open_Rack_Optical_Interconnect_Design_Guide_v0.5.pdf

MXC Connector

MPO Connector

page 9

• 2x16 MT

• 2x12 MT

MultiFiber Physical Contact MT Ferrule Comparison

page 10

MT Ferrule Prism MT Ferrule

Ferrule

Alignment

Dust

HigherDensity

MT and Prism ® MT FerrulesPhysical contact ferrules compared to lensed ferrules

page 11

Proposed Optical Lane Assignment for SR16(Looking into the module)

Page 11

Rx <-------- -------Rx Tx <----- --------Tx

Tx------- -------Tx Rx ------- -------Rx

• MPO

• MXC™Rx ------- -------Rx Tx <------- --------Tx

Tx-------- --------Tx Rx ------ -------Rx

XPin

Hole

Consistent with CDFP MSA

Benefits of this Proposal

• Provides a near term solution for 400Gb/s 100m objective• Using CDFP as a possible form factor delivers a density increase

over 3 times 4x100GBASE-SR4 discrete modules– www.cdfp-msa.org

• Other form factors are possible• Reuse of Clause 95 parameters allows compatibility between 100G

and 400G• 400Gb/s links could be single module to 4 discrete modules• Also supports breakout cabling capability

CDFP 400Gb/s

4xQSFP28 400Gb/spage 13